System and method of converting frame-based animations into interpolator-based animations

ABSTRACT

A system and method of converting frame-based animation into interpolator-based animation is provided. The system and method includes a) identifying each unique combination of animation object and associated depth identified in frame instructions for the plurality of frames of the frame-based animation; b) for each identified unique combination, identifying the display properties associated with the animation object of the combination through the successive frames; and c) for each identified display property for each identified unique combination, creating an interpolator that specifies the animation object of the combination and any changes that occur in the display property for the specified animation object throughout the plurality of frames.

This application claims priority to U.S. Provisional Patent ApplicationsSer. No. 60/429,570 filed Nov. 29, 2002 and Ser. No. 60/447,022 filedFeb. 13, 2003, the entire disclosures of which are incorporated hereinby reference.

BACKGROUND

1. Field of the Invention

This invention relates generally to computer animations and specificallyto formats for representing computer animations.

2. Description of the State of the Art

Two types of formats are predominantly used to represent computeranimations: frame-based animation formats and interpolator-basedanimation formats. These types of animation formats differ fundamentallyin how they represent computer animations, thus computer software thatdisplays frame-based animations is typically unable to displayinterpolator-based animations.

In frame-based animation formats, an animation is comprised of a groupof animation objects and a series of frames. Each frame comprisesanimation objects which are displayed at a particular time in theanimation, and properties which specify how the objects are displayed.Computer software that displays a frame-based animation displays theframes in the animation sequentially. When animation objects areincluded in successive frames with different properties, the objectsappear to be moving or otherwise changing when the computer softwaredisplays the frames of the animation.

In interpolator-based animation formats, an animation is comprised of agroup of animation objects and a group of interpolators. Eachinterpolator specifies how a property of an animation object changesover time. For example, an interpolator may specify that a rectangleappears at the bottom-left corner of a computer display, travels to thetop-right corner of the computer display, and takes five seconds to doso. Computer software that displays an interpolator-based animationdisplays the animation objects and manipulates the properties of theanimation objects over time as specified by the interpolators, thuscreating the appearance that the animation objects are moving orotherwise changing.

An interpolator-based animation often consumes less storage space than aframe-based animation which appears the same when displayed, since asingle interpolator can specify a movement that would require manyframes to specify. Minimizing storage space is especially beneficialwhen animations are displayed on mobile communication devices, sincethey often have limited amounts of computer memory and processingcapacity. Mobile communication devices also typically have limitedbandwidth with which to communicate via wireless networks.

When displaying interpolator-based animation, the rendering device isgenerally at liberty to vary the rate at which the display is updated.In frame based animation, the frame rate is typically set at a constantrate. The rate flexibility available in interpolator-based animationallows a rendering device to reduce the display rate, which can beuseful in the resource and power limited environment of a mobile device.

Thus, an efficient system and method for converting frame-basedanimations to interpolator-based animations is desired.

SUMMARY

A method for converting a frame-based animation into aninterpolator-based animation, the frame based animation including aplurality of animation objects and a plurality of successive framesrepresented by frame instructions, the frames including a displayedgroup of the animation objects. The animation objects in the displayedgroup have associated display properties that change throughout thesuccessive frames, and the animation objects in the displayed group eachappear at a unique associated depth in the frames. The frameinstructions identify for each frame the animation objects from thedisplayed group appearing therein and the display properties and depthassociated with each of the animation objects appearing therein. Themethod including steps of: a) identifying each unique combination ofanimation object and associated depth identified in the frameinstructions for the plurality of frames; b) for each identified uniquecombination, identifying the display properties associated with theanimation object of the combination through the successive frames; andc) for each identified display property for each identified uniquecombination, creating an interpolator associated with the animationobject of the combination which specifies any changes that occur in thedisplay property for the specified animation object throughout theplurality of frames.

A converter for converting a frame-based animation into an interpolatorbased animation, the frame-based animation including a plurality ofanimation objects each having an associated type identifier and aplurality of successive frames represented by frame instructions, theframes including a displayed group of the animation objects, theanimation objects in the displayed group having associated displayproperties that change throughout the successive frames, the animationobjects in the displayed group each appearing at a unique associateddepth in the frames. The frame instructions specify for each frame theanimation objects appearing therein, and display properties andassociated depth of the animation objects appearing therein. Theinterpolator based animation includes the plurality of animation objectsand a plurality of interpolators, each interpolator being associatedwith a target display property of a target animation object typeselected from the plurality of animation objects and specifying changesthat occur in the target display property during a display duration. Theconverter includes: an input module for receiving a frame basedanimation and extracting the frame instructions therefrom; a convertermodule for (a) receiving the extracted frame instructions from the inputmodule and based thereon identifying each unique combination ofanimation object and associated depth appearing in the plurality offrames, and (b) for each identified unique combination, identifying thedisplay properties associated with the animation object of thecombination through the plurality of frames; and an output moduleresponsive to the converter module for creating for each identifieddisplay property for each identified unique combination an interpolatorspecifying (i) the identified display property as a target displayproperty, (ii) the animation object of the combination as a targetanimation object, and (iii) any changes that occur in the displayproperty for the specified animation object throughout the plurality offrames.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an animation system in accordance with anembodiment of the invention;

FIG. 2 is a block diagram of a system of converting frame-basedanimations into interpolator-based animations;

FIG. 3 is a flow-chart illustrating a method of converting a frame-basedanimation into an interpolator-based animation;

FIG. 4 is a block diagram of a communication system to which theanimation conversion system may be applied in accordance with exampleembodiments of the present invention;

FIG. 5 is a block diagram of the content provider system of FIG. 4;

FIG. 6 is a block diagram of the converter of FIG. 5;

FIG. 7 is a block diagram of one of the media devices of FIG. 4;

FIG. 8 is a block diagram of the media engine of FIG. 7;

FIG. 9 is a block diagram of a conversion of an animation;

FIG. 10 is a block diagram of an example of the visual elements of FIG.9 represented as a visual graph;

FIG. 11 is a block diagram of an example of the behavior elements ofFIG. 9 represented as a sequence graph;

FIG. 12 is a flowchart of a method of converting rich content into abinary format;

FIG. 13 is a block diagram of an example animation; and

FIG. 14 is a block diagram of a dual-mode mobile communication device.

DETAILED DESCRIPTION

FIG. 1 is a block diagram of an animation system in accordance with anembodiment of the invention. The animation system includes a frame-basedanimation creator 100, frame-based animations 102, an animationconverter 104, interpolator-based animations 106, and aninterpolator-based animation viewer 108.

The frame-based animation creator 100 is used to create frame-basedanimations 102. The frame-based animation creator 100 is implemented ascomputer software which is executed by a computer.

Each of the frame-based animations 102 comprises a group of animationobjects 110, including shapes, images, buttons and text, and a series offrame instructions 112 representing successive display frames. In anexample embodiment, the frame-based animation 102 is an electronic filethat includes the information necessary for a frame based renderingdevice to display the frames that are represented in the frame-basedanimation 102. Such information includes the animation objects, whicheach have an associated identifier, and the frame instructions. Theframes each include a displayed group of the animation objects, and arecreated using a display list 114, which specifies which of the animationobjects are displayed in the current frame and display properties ofsuch animation objects. The display list is created and then modifiedfor successive frames by the frame instructions, which includeinstructions to add or remove animation objects to the display list, andto change the display properties as required for the frame associatedwith the frame instructions. The display properties include theposition, color, scale, rotation and skew of animation objects that aredisplayed in the frame. A frame is created by manipulating the displaylist, by adding, removing or changing animation objects, and thenrendering the frame according to the contents of the display list.

Each of the animation objects is added to the display list at aparticular depth that is specified in the frame instructions. The depthsof the animation objects determine the order in which the animationobjects are rendered. The display list contains at most one animationobject at a particular depth. Different instances of the same animationobject can appear at different depths in each frame.

Thus, the frame-based animations 102 are represented in computer memoryas data that defines animation objects 110 and computer instructions 112for creating frames that include selected animation objects. Each of thecomputer instructions for a frame specifies that an animation objectshould be added to the display list 112, that an animation object shouldbe removed from the display list 112, that new display properties shouldbe set for an animation object in the display list, or that a frameshould be rendered according to the contents of the display list.

A frame-based animation is displayed by computer software by displayingeach of the frames of the frame-based animation sequentially. Each frameis displayed for an identical period of time, which is determined by aconfigurable frame-rate. A frame-rate is expressed as a number of framesdisplayed per time-unit, and is typically frames-per-second. Theanimation objects in each frame are displayed in an order determined bythe depth values associated with the animation objects. Animationobjects which are assigned lower depth values are displayed underneathanimation objects which are assigned higher depth values.

The animation objects in the frame-based animations 102 also includesprites, which are independent animations within a frame-basedanimation. Each sprite comprises animation objects and frames asdescribed above. When a sprite is added to a display list and renderedin a frame of a frame-based animation, the frames in the sprite aredisplayed concurrently with the frames in the frame-based animation.Each sprite has a looping property, which specifies whether the framesin the sprite are displayed continuously during the frame-basedanimation, so that when the last frame in the sprite is displayed, thesprite continues to be displayed starting with the first frame.

The interpolator-based animation viewer 108 is used to viewinterpolator-based animations 106. The interpolator-based animationviewer 108 is implemented as computer software which is executed by acomputer, or alternatively by a mobile computing device. Theinterpolator-based animations 106 are represented by data in computermemory.

Each of the interpolator-based animations 106 comprises animationobjects 116, including shapes, images, buttons and text. The animationobjects each have associated display properties including position,visibility, color, scale, rotation and skew.

Each of the interpolator-based animations 106 further comprises a groupof interpolators 120, which specify values for the display propertiesfor each of the animation objects 116 over time. Each interpolatorspecifies a duration, a target animation object, a target displayproperty of the target animation object, a set of key-times, and a valueof the target display property for each of the key-times. The key-timesare normalized from zero to one.

The interpolator-based animation viewer 108 displays aninterpolator-based animation by rendering the animation objects asspecified by the interpolators. For each interpolator, theinterpolator-based animation viewer 108 sets the target display propertyof the target animation object at the times specified by the key-times.The time that a target display property is set for a particular key-timeis the product of the key-time and the duration specified by theinterpolator.

For example, an interpolator may specify a duration of 10 seconds, atarget animation object which is a square, a target display propertywhich is the x-coordinate of the position of the square, key-times of 0,0.5 and 0.6, and corresponding values of 0, 100 and 200. At thebeginning of the animation, the interpolator-based animation viewer 108sets the x-coordinate of the square's position to 0, then five secondsinto the animation, the interpolator-based animation viewer 108 sets thex-coordinate of the square's position to 100, then six seconds into theanimation the interpolator-based animation viewer 108 sets thex-coordinate of the square's position to 200.

In an alternative embodiment, the key times are not be normalizedbetween zero and one, but instead are units of real time, in which casea duration value is not required.

The animation objects specified by the interpolators are displayed inthe order in which the animation objects are processed by theinterpolator-based animation viewer 108. Animation objects which areprocessed first are displayed underneath animation objects which aresubsequently processed. The animation objects are processed in the orderin which they are specified in each of the interpolator-based animations106.

The animation converter 104 converts frame-based animations 102 createdby the frame-based animation creator 100 into equivalentinterpolator-based animations 106 which can be viewed with theinterpolator-based animation viewer 108. When viewed, a frame-basedanimation and the equivalent interpolator-based animation which isproduced by the animation converter 104 appear the same. The animationconverter 104 implements a system of converting frame-based animations102 into interpolator-based animations 106 as is shown in FIG. 2. Theanimation converter 104 is implemented as computer software which isexecuted by a computer.

FIG. 2 is a block diagram of animation converter 104, which implements asystem of converting frame-based animations into interpolator-basedanimations. The animation converter system includes a frame-basedanimation input module 200, a conversion module 202 and aninterpolator-based animation output module 204.

The frame-based animation input module 200 receives a frame-basedanimation 102 as input. The frame-based animation 102 is represented bybinary data in a computer-readable file, and is comprised of animationobjects 110 and frames instructions 112. The frame instructions 112represent frames and are computer instructions to add animation objectsto a display list 114, remove animation objects from the display list114, change properties of animation objects in the display list 114, andrender frames based on the contents of the display list 114, asdescribed above. The frame-based animation input module 200 reads thecomputer instructions 112 and recreates the contents of the displaylist, thereby determining the content of each of the frames representedin the frame-based animation. For each instance of an animation objectbeing displayed in a frame, the values of the display properties anddepth of the animation object are also determined. The frame-rate of theframe-based animation is also determined.

The conversion module 202 uses the animation objects 110 received by theframe-based animation input module 200 and the frame informationdetermined by the frame-based animation input module 200 to create a map206 that will be used by the interpolator-based animation output module204.

The display properties (dp1, dp2, . . . ) for each animation object ineach of the frames is recorded in the map 206. For each animation objectat each depth, a key 208 is created. The key 208 comprises a uniqueidentifier for the animation object, and the depth at which theanimation object is displayed in the frame. In one embodiment the uniqueidentifier for the animation object is an object type identifier. Thecreation of a key that combines an object type identifier with an objectdepth allows multiple instances of an object in a frame based animation102 to be uniquely identified. As noted previously, in frame basedanimations, more than one instance of the same animation object canappear in the same frame, but at different depths. Thus, the same objecttype identifier can appear multiple times, but at different displaydepths, in a frame. The keys 208 are thus created so that there is aunique key for each unique combination of animation object and depth.

The keys 208 are represented in computer memory by 32-bit integers. Themost significant 16 bits specify the depth at which the animation objectis displayed, while the least significant 16 bits specify the animationobject's unique identifier, which allows the keys to be sorted by thedepth values. A different number of bits may alternatively be used torepresent the key.

The value mapped to each key 208 is a table 210, which comprises a setof key-times (key-time x, key-time x+1, etc.), a set of displayproperties (dp1, dp2, etc.), and for each of the key-times, a value foreach of the display properties.

The conversion module 202 creates the map 206 by iterating through theframes in the animation. For each animation object in each frame, a key208 is created, as described above. If the key 208 is not present in themap, then the key is added to the map 206, and an associated table 210is created. If the key 208 is present in the map, then the associatedtable 210 to which the key maps is retrieved. If at least one of thedisplay properties (dp) for the animation object has changed since theprevious time the table 210 was updated, then an entry is added to thetable which specifies a key-time, and a value for each of the displayproperties for the animation object in the frame. The key-time iscalculated based on the position of the frame in the animation, and theframe-rate. Each frame in the animation is displayed for a period oftime equal to the inverse of the frame-rate, so the key-time for a givenframe is the position of the frame, multiplied by the inverse of theframe-rate. The key-times are normalized from zero to one, and theduration of the animation is recorded in the table. The duration is thenumber of frames divided by the frame-rate.

For example, if there are 100 frames in an animation, and the frame-rateis 20 frames per second, then the duration of the animation is 5seconds. Each frame is displayed for 1/20 seconds. The key-times aredetermined to be 1/20 seconds for the first frame, 2/20 seconds for thekey-time for the second frame, 3/20 seconds for the key time for thethird frame, and so on. The key-times are then normalized so that eachkey-time is a value from zero to one.

Where an animation object at a particular depth is not present in everyframe in the frame-based animation, the visibility display property isincluded in the table corresponding to the animation object in the map.If the animation object is not present in a frame, then the visibilitydisplay property specifies that the animation object is not visible.

When the conversion module 202 has iterated through all the frames, themap contains a unique key for each animation object at each depth, and acorresponding table which contains the values for each display propertyof the animation object for each time that one of the display valueschanges in the animation. The mapping ensures that only one table iscreated for an animation object at a particular depth in an animation,even where the animation object is not included in every frame.

Where an animation object is a sprite, for each animation object in eachframe in the sprite, a key and a table are added to the map as describedabove. In tables for animation objects which are included in a sprite,the key-times correspond to the position of the frame in the sprite, andthe duration recorded is the number of frames in the sprite, divided bythe frame rate. The table to which the key corresponding to the spritemaps contains a visibility property, which specifies whether the sprite,including all the animation objects contained in the sprite, is visibleat different times in the animation. The table also contains a displayproperty which specifies whether the sprite loops, as described above.

The interpolator-based animation output module 204 uses the map 206created by the conversion module 202 to create interpolators 120 for theinterpolator-based animation 106 which is outputted by the system ofconverting frame-based animations into interpolator-based animations.

The map 206 is sorted in ascending order by the value of the keys. Sincethe most significant bits of the keys specify the depths of theanimation objects, the sorted map is ordered according to the depths ofthe animation objects in the frames.

For each key in the map, an interpolator 120 is created by theinterpolator-based animation output module 204 for each display propertyfor which there are values in the table to which the key maps. For eachinterpolator created for a display property for which there are valuesin the table mapped to by one of the keys in the map, the targetanimation object is the animation object specified in the key. Thetarget display property is the display property for which there arevalues in the table. The key-times specified by the interpolator are thekey-times contained in the table. The values which correspond to the keytimes are the values for the display property which are specified in thetable. The duration specified by the interpolator is the durationrecorded in the table, as described above.

The interpolator-based animation output module 204 outputs aninterpolator-based animation comprising the animation objects and theinterpolators. The animation objects are specified by theinterpolator-based animation in an order corresponding to the order ofthe keys in the map, so that animation objects of lesser depths arespecified first, and animation objects of greater depths are specifiedlast. The order ensures that when the outputted interpolator-basedanimation is displayed, the animation objects will be rendered in anorder which is equivalent to the depths specified by the inputtedframe-based animation.

The interpolator-based animation is outputted in extensible markuplanguage (XML) format to a computer-readable file.

FIG. 3 is a flow-chart illustrating a method of converting a frame-basedanimation into an interpolator-based animation, which in an exampleembodiment is carried out by animation converter 104. The methodreceives an inputted frame-based animation 102 and creates and outputsan equivalent interpolator-based animation. The frame-based animation102 contains animation objects and frames, as described above.

The method beings with step 302 of reading the animation objects 110which are included in the frame-based animation 102. The methodcontinues with step 303 of creating a map 206 to store information fromthe frame-based animation 102 which is used to create the equivalentinterpolator-based animation.

The method continues with step 304 of determining whether there areframes in the frame-based animation 102 which have not yet been read.The frames are represented in the frame-based animation 102 by computerinstructions 112 to add an animation object to a display list 114,remove a display object from the display list, change the properties ofan animation object in the display list, and render a frame based on thecontents of the display list. There are more frames to read if there aremore computer instructions 112 in the frame-based animation 102 whichspecify that a frame should be rendered.

If it is determined at step 304 that there are no more frames to read,then the method continues at step 326. If there are more frames to read,then a frame is read at step 306. The frame is read by reading computerinstructions 112 as described above.

The method continues by iterating through the animation objects whichare in the displayed group of animation objects in the frame read atstep 306. An animation object may appear at different depths in a singleframe, in which case the animation object appears once in the iterationfor each depth at which the animation object appears in the frame. Nomore than one animation object may appear at a single depth in a frame,thus an animation object cannot appear more than once with the samedepth.

The animation objects which are displayed in the frame read at step 306may include sprites, in which case each of the animation objects in thesprites are included in the iteration.

Step 308 determines whether all the animation objects displayed in theframe have been iterated. If there are more animation objects displayed,then the method continues at step 310. Otherwise, the method continuesat step 304.

At step 310, the properties of an animation object in the frame read atstep 306 are read. The properties include the depth of the object in theframe, and display properties including position, color, scale, rotationand skew.

The method continues with step 312 of creating a key 208 which specifiesthe animation object whose properties are read at step 310 and the depthof the animation object. Since the same animation object does not appearmore than once with the same depth in a frame, the combination ofanimation object identifier and depth constitutes a unique key.

The method continues with step 314 of determining whether the key 208created at step 312 is in the map 206 created at step 303. If it isdetermined that the key 208 is not in the map 206, then the key is addedat step 316. The method then continues at step 318, where a table 210associated with the key is created to store the display properties readat step 310, associated key-times, and a duration value. The map 206 isupdated so that the key 208 created at step 312 maps to the newlycreated table 210.

The method then continues at step 324, where the table 210 created atstep 318 is updated. A new key-time which corresponds to the position ofthe frame is added to the table. If the animation object for whichproperties are read at step 310 is not included in a sprite, then thekey-time is equal to the position of the frame in the frame-basedanimation 102, multiplied by the inverse of the frame-rate. If theanimation object is included in a sprite, then the key-time is equal tothe position of the frame in the sprite, multiplied by the inverse ofthe frame-rate. The key-times in the table are normalized such that thekey-times are values from zero to one.

The duration value is updated based on the frame-rate. If the animationobject is not in a sprite, then the duration is the number of frames inthe frame-based animation 102 divided by the frame-rate. If theanimation object is in a sprite, then the duration is number of framesin the sprite divided by the frame-rate.

For each display property read at step 310, a value for the displayproperty is entered into the table 210 so that it is associated with thekey-time. The method then continues at step 308.

If it is determined at step 314 that the key created at step 312 doesexist in the map 206 created at step 303, then the method continues atstep 320, where the table 210 to which the key maps is retrieved. Themethod then continues at step 322, where it is determined whether thevalues of the display properties of the animation object for whichproperties were read at step 310 have changed since they were recordedin the table 210. If the display properties read at step 310 differ fromthe display properties recorded in the table 210, then the table isupdated at step 324. Otherwise, the method continues at step 308.

The method continues at step 326, where it is determined at step 304that there are no more frames to read. The map created at step 303contains keys 208 for each combination of animation object and depth inthe frame-based animation 102. The tables to which the keys map containvalues for each of the display properties of the animation objects atkey-times which correspond to the frames. At step 326, the keys createdat step 312 are sorted in ascending order. This ensures that the keyswhich specify lesser depths appear first in the map.

The method continues with step 328 of creating interpolators based onthe contents of the map 206 created at step 303. An interpolator iscreated for each display property in each table created at step 318. Thetarget animation object specified by the interpolator is the animationobject whose unique identifier is included in the key which maps to thetable. The target display property specified by the interpolator is thedisplay property included in the table. The key-times specified by theinterpolator are the key-times in the table. The display property valuesassociated with the key-times specified by the interpolator are thevalues of the display properties in the table which correspond to thekey-times in the table. The duration specified by the interpolator isthe duration recorded in the table.

The method concludes with step 330 of outputting an interpolator-basedanimation which is equivalent to the inputted frame-based animation 102.The interpolator-based animation comprises the animation objects read atstep 302, and the interpolators created at step 328. The animationobjects are outputted in an order corresponding to the order of the keysin the map, so that when the interpolator-based animation is displayed,the animation objects specified by the interpolators are displayed in anorder which corresponds to the depths specified in the frame-basedanimation 102.

The method illustrated in FIG. 3 may contain additional, fewer, ordifferently ordered steps than those which are shown. For example, insome embodiments, the keys in the map could be sorted each time a newkey was added at step 316, rather than at step 326 after all the keyshave been added.

FIG. 4 is a block diagram of a communication system in which ananimation conversion system of the present invention may be applied. Thecommunication system comprises media devices 405 for presenting content,a wireless network 410 for communicating with the media devices 405, awireless network gateway 415 for interfacing the wireless network 410with a wide area network (WAN) 420 for connecting the wireless networkgateway 415 to a content provider system 425.

The wireless network gateway 415 provides an interface between thewireless network 410 in which the media devices 405 operate, and the WAN420 in which the content provider system 425 is configured to operate.The WAN 420 comprises the Internet, a direct connection, a local areanetwork (LAN), a wireless communication link, and any combinationsthereof.

The content provider system 425 provides the content for presentation onthe media devices 405. The content is provided in a binary format forprocessing by the media devices 405. The binary format is substantiallythe content as it is to exist in memory on the media devices 405, with aheader. The content includes rich content.

The media devices 405 include, for example, data communication devices,multiple-mode communication devices configured for both data and voicecommunication, mobile telephones, mobile communication devices, PDAsenabled for wireless communications, 1-way or 2-way pagers, wirelessmodems operating in conjunction with computer systems, and any type offixed or mobile wireless communication devices. Each of the mediadevices 405 is configured to operate within the wireless network 410. Areceiver and transmitter subsystem or transceiver (not shown) isincluded within each of the media devices 405 for operation the wirelessnetwork 415. It should be appreciated however that the invention is inno way limited to these example types of devices and may be implementedin other devices with displays.

Alternately, the content provider system 425 may also provide content toany system connected to the WAN 420, including both wireless gateways aswell as non-mobile systems such as desktop computer systems.

FIG. 5 is a block diagram of the content provider system of FIG. 1. Thecontent provider system 425 comprises a data store 500 for storing thecontent, an application 505 to access and process the content forpresenting on the media devices 405, a converter 510 for converting thecontent into the binary format, an external animation converter 104 forconverting content for storage in the data store 500, and acommunication subsystem 515 for sending the content in binary format.

The data store 500 stores the content on a hard disk of a servercomputer in which the content provider system 425 is implemented. Thecontent is authored and stored in eXtensible Markup Language (XML) and,in particular, in the Scalable Vector Graphics (SVG) format of XML forgraphics including animations. In the presently described embodiment,the content includes interpolator-based animations 106 that are storedin SVG format. Thus, the external animation converter 104 convertsframe-based content to the interpolator-based content for storage in thedata store 500.

The application 505 includes an application server. Alternatively, theapplication 505 may comprise an application executing on an applicationserver. Alternatively, the application 505 may further comprise anapplication for a particular service executing on an application server.

The converter 510 processes the content for rendering on the mediadevices 405. This processed content is provided in the binary format tofurther lessen processing at the media devices 405. Thus, some of thecontent processing is offloaded from the media devices 405 to thecontent provider system 425.

The media devices 405 request content from the content provider system425 via standard HTTP requests and, in response, the content providersystem 425 provides the content in binary format to the media devices405, where the content is displayed and content-related operations,including user inputs, are performed.

Alternatively, the data store 500 may be an external data store,including a web server for example, accessible to the content providersystem 425 through a network or other connection.

While the content provider system 425 as described includes an externalanimation converter 104 which converts rich content from a frame-basedformat to the SVG interpolator based format and a converter 510 whichconverts from SVG to a binary format, either or both conversions mayalternatively be performed by either the converter 510 or the externalanimation converter 104. For example, the combined converter may convertboth from frame-based content to interpolator-based SVG, and from SVG tothe binary format, so that frame-based content could be stored in thedata store 500 and converted into the binary format following a requestfor the content.

Like the gateway 415 and the media devices 405, the design of thecommunication subsystem 515 in the content provider system 425 dependsupon the communication networks and protocols used by the contentprovider system 425. The communication subsystem 515 includes suchcomponents as are required to communicate within the WAN 420. Thoseskilled in the art will appreciate that the communication subsystem 515may also include systems for processing content requests, where contentis provided in response to requests. The communication subsystem 515 mayalso include further or alternate systems and arrangements commonlyassociated with content provider systems.

FIG. 6 is a block diagram of the converter 510 of FIG. 5. The converter510 comprises an SVG reader 600 for reading the content in SVG andformatting the content into an SVG Document Object Model (SVG DOM) 605,an SVG compiler 610 for converting the SVG DOM 605 to a binary format(BF) Object Model 615, and a BF writer 620 for writing the BF ObjectModel 615 of the content into the binary format.

The SVG DOM 605 is an in-memory version of the content for access by theSVG compiler 610. The BF Object Model 615 is an in-memory version of thecontent as rendered on the media devices 405. The SVG Compiler 610filters the SVG DOM 605 to discard elements of the DOM that are notsupported by the BF Object Model 615 and then the filtered SVG DOM 605is analyzed and built into the BF Object Model 615. The binary format issubstantially a memory map or dump of the BF Object Model 615 plus theheader.

As noted above, the external animation converter 104 includes, in anexample embodiment, a frame-based animation input module 200, aconversion module 202, and an interpolator-based animation output module204. The frame-based animation input module 200 receives a frame-basedanimation, which is an example of frame-based content which is convertedby the animation converter 104, as input. In addition to the contentdescribed above frame-based animations can also contain script, which isa sequence of commands written in a scripting language. Script isincluded in a frame-based animation and is executed by softwaredisplaying the animation in response to actions such as button actionsand frame actions. Button actions occur when a user clicks a mousepointer on an animation object such as a button. Frame actions occurwhen a frame containing the script is displayed.

Script commands which can be included in a frame-based animation includea get-URL command, which loads content from a network location specifiedby a Uniform Resource Locator (URL). Script commands further include atell-target command, a play command, and a stop command. The tell-targetcommand specifies a target sprite to which subsequent play and stopcommands apply. The play command specifies that display of the targetsprite should commence, while the stop command specifies that thedisplay of the target sprite should cease. The set of script commandswhich can be used in the system and method described is not limited tothe script commands described above.

As noted previously, based on the output of frame-based animation inputmodules 200, the conversion module 202 creates a map comprising a keyfor each unique combination of one of the animation objects in thedisplayed groups and one of the depth values associated with theanimation object. Each key comprises a unique identifier for theanimation object and the depth value. Each key maps to a table whichcomprises a set of key-times corresponding to positions of the frames,the display properties of the animation object, values of the displayproperties for each of the key-times, and a duration value which iscalculated based on the frame-rate.

The interpolator-based animation output module 204 then creates andoutputs an interpolator-based animation in SVG format. Theinterpolator-based animation comprises the animation objects and aplurality of interpolators. For each of the display properties in eachof the tables in the map, one of the interpolators comprises a targetanimation object which is the animation object identified in the keywhich maps to the table, a target display property which is the displayproperty, the key-times included in the table, the values of the displayproperty included in the table, and the duration value included in thetable.

Each interpolator created by the interpolator-based animation outputmodule 204 is outputted as an SVG animate tag. Script contained in theframe-based animation is also outputted in SVG format, as describedbelow. The SVG content outputted from the external animation converter104 is inputted into the data store 500, at which point the content isavailable to the application 505.

FIG. 7 is a block diagram of one of the media devices of FIG. 4. Themedia device 405 comprises a device communication subsystem 525 forinterfacing with the wireless network 410 to receive the content and tosend content related requests such as user inputs, a media engine 530for reading and rendering the received content including interpretingcontent related requests, a device infrastructure 535 with memory forsupporting the operations of the media device 405, a display 540 forpresenting the content, and a keyboard/keypad 545 and an auxiliary inputdevice 550 for receiving the user inputs. The user inputs includerequests for content from the content provider system 425. The auxiliaryinput device 550 includes a rotatable thumbwheel, a special functionkey, and a pointer.

The media engine 530 enables such rich content operations as imagerendering, sprite animation rendering, filled and unfilled rectanglerendering, polygon, point, and polyline rendering, text rendering, andtext font and style selection. Such advanced operations as constant,linear and cubic animation paths, object positions and color, and audioclip rendering are also preferably supported by the media engine 510.

FIG. 8 is a block diagram of the media engine of FIG. 7. The mediaengine 530 comprises a reader 570 for reading the received content inbinary format, formatting the received content to the BF Object Model615 and placing in the memory of the media device 405, and a renderer565 to render the received content, the BF Object Model 615, forpresenting on the display 540 and for supporting content-relatedoperations.

FIG. 9 is a block diagram of a conversion of an animation. The animation700 is an example of rich content provided by the content providersystem 425. The animation 700 is converted first by the external frameto interpolator-based animation converter 104, and then by the converter510. For simplicity, the remaining elements of the content providersystem 425 are not shown in FIG. 7.

The external converter 104 converts the animation 700 from a frame-basedformat to the SVG format, as described above. As those skilled in theart will appreciate, the animation 700 in the SVG format has visualelements associated with behavior elements, and is represented by an SVGDOM 605. The converters 104, 510 separates the animation 700 into visualelements 710 and behavior elements 720, and builds the BF Object Model615 with separate visual and behavior elements. The visual elements 710include text, lines, colors, and shapes, whereas the behavior elements720 include operations, such as changing colors and changing positionsof the visual elements 710 over time.

FIG. 10 is a block diagram of an example of the visual elements 710 ofFIG. 9 represented as a visual graph. The visual graph 800 is composedof nodes, including groups and leaves, as shown. The visual graph 800includes two groups, namely group A 805 and group B 810, and threeleaves, namely the rectangle 815, image 820, and text 825. A grouprepresents a transformed sub-universe, whereas leaves represent visualobjects and attributes such as images, text, and primitives includinglines, ellipses, and rectangles. The top level group A 805 has twochildren, one of which is the group B 810 and the other of which is aleaf, the rectangle 815. The group B 810 has two children of its own,each of them a leaf, namely the image 820 and the text 825. Grouping ofnodes in a visual graph allows transformations, such as translations androtations for example, to be applied to all elements of a group. Thegroup nodes 805, 810 are also used to set graphics coordinates to beused when rendering visual elements in a group or subordinate group.

The rectangle 815 is a primitive that is a rectangle with its top leftcorner at coordinates 0,0, a length of 10 pixels, a height of 24 pixels,and a color of red. The image 820 is an image of a face in GIF format.The text 825 is a text leaf with the text “Hello, World” starting atcoordinates 0,0.

At the media device 405, the visual graph 800 is rendered by processingthe nodes in a predetermined order, by starting at a root node andtraversing leftmost nodes first (i.e. pre-order traversal). In thevisual graph 800, the root node, the group A 805, is processed first.The group A 805 resets an origin of a graphics coordinate system for allelements in its sub-universe to coordinates x=10 and y=20. Therefore,all rendered components in the sub-universe of group A 805 are drawnrelative to the translated origin at 10,20.

Traversing the visual graph 800 in a pre-order traversal, the group B810, is processed next, which further translates the origin of thegraphics coordinate system along a y axis. The visual elements in thesub-universe of group B 810 are rendered relative to its origin at10,24. The image 820 is processed next and the image “face.gif” isdisplayed on the display 520 at the group B 810 origin of 10,24. Sincethe image 820 is a leaf, the rendering process returns to the groupnode, the group B 810, and then proceeds to the text 825. The text“Hello, World” is then drawn starting at coordinates 0,0 in thesub-universe of the group B 810, which is at absolute coordinates 10,24.The text 825 is also a leaf, such that the rendering process returns tothe group node, the group B 810. Since all of the children of the groupB 810 have been processed, control then returns to the group A 805 andgraphical coordinates are reset to the sub-universe of the group A 805,with origin at 10,20. The rectangle 815 is then rendered to draw the redrectangle, at the origin of its sub-universe (10,20).

An algorithm, such as the SVG painter's model, is used to control theappearance of overlapping visual elements on a display screen. Accordingto this algorithm, each visual element drawing operation “paints” oversome area of an output device display screen. When this area overlaps apreviously painted area, the new paint partially or completely obscuresthe old. Each visual element is drawn over any overlapping portions ofpreviously drawn elements at the same location on the display screen.Therefore, background visual elements, which are to appear “deeper” in adisplayed scene, are located in a visual graph so as to be drawn first,and foreground elements are drawn on top of previously drawn elements.In the visual graph 800, the red rectangle 815 is drawn on top of anyoverlapping sections of the previously drawn “face.gif” image 820 andthe text “Hello, World” 825.

The visual graph 800 is an example and is intended for illustrativepurposes only. The structure and arrangement of any visual graph willdepend upon the visual elements in a scene to be displayed. Differentelements than those shown in FIG. 8 may have further or differentattributes. For example, an ellipse may be defined by its centerlocation and the lengths of its major and minor axes, instead of thecorner location, width and height shown for the rectangle in leaf 815. Arectangle or other shape may include further or alternative attributesthan those shown in leaf 815, such as a different corner or centerlocation instead of top left corner coordinates, fill properties, andline type designations. Similarly, text visual elements may have suchattributes as font, color, and size.

FIG. 11 is a block diagram of an example of the behavior elements 720 ofFIG. 9 represented as a sequence graph. The sequence graph 900 is basedon the premise that the visual elements 710 have time-based behaviors.These time-based behaviors are used to construct behaviors that are usedto both schedule the animation 700 and make it behave as intended. Thebehavior elements 720 reference the visual elements 710 as necessary toapply the appropriate behaviors to create the animation 700.

It will be apparent to those skilled in the art that the animation 700in SVG format requires a scheduler in order to manage the behaviors ofvisual elements. Separation of the behavior elements 720 in the sequencegraph 900 from the visual elements 710 in the visual graph 800 inaccordance with this aspect of the invention does not need a separatescheduler to process the animation 700. Scheduling is inherent in thesequence graph 900, which reduces the requirements of the media engine530 and further provides a method of providing thread-safe convertedcontent.

The sequence graph 900 describes how a scene behaves over time. Thesequence graph consists of behaviors and behavior sequencers. Behaviorsinclude such operations as hotspots, hyperlinks, keypad events, textentry, animation/interpolation, timers, variable settings, play/stopaudio, visual graph modification, and other behaviors. The behaviors arebounded by such behavior sequencers as linear sequences, all-fork,any-fork, and if-else-fork sequencers.

A hotspot is a special aggregated sensor/behavior that allows visualelements in the visual graph of a scene to be tagged as hotspots. Thisallows behaviors to be executed depending on the status of navigation ofthose hotspots using a cursor, pointer or the like, on a device on whichthe scene is displayed. Hyperlinks are used to load more content fromthe network and are similarly dependent upon navigation and selection ofa visual element on a display screen. Keypad events and text entry mayalso invoke other dependent behaviors.

Animation and interpolation are behaviors that apply to attribute dataof various objects. An interpolation, for example, may define aninterpolation curve along which one or more visual elements may bemoved. Timers are used to set pauses of specified duration. Variablesettings set the value of a variable or attribute. Play/Stop audiobehavior provides for controlled playing of an audio clip. An audio clipmay be played in its entirety, stopped after a predetermined timeduration, using a timer, for example, or stopped when a user navigatesto a display screen hotspot, for example.

Some of these behaviors affect visual elements of an animation. When avisual element is to be changed, the sequence graph references theappropriate element of the corresponding visual graph and modifies theelement in the visual graph. The visual graph is then rendered again toreflect changes to visual elements.

A behavior sequencer controls the execution of its associated behaviorsor child nodes in a sequence graph. One such behavior sequencer is alinear sequence, in which each child node is executed in order. A linearsequence is completed when all of its child nodes have finishedexecuting. Looping may be enabled or disabled in any linear sequence,and each child node is executed during each pass of the loop. A loop ina linear sequence is complete when all child nodes have finishedexecuting, whereas an entire looped linear sequence is completed whenall of its child nodes have been executed a particular number of timesspecified in the linear sequence behavior sequencer in the sequencegraph. If a linear sequence is to continue indefinitely, then infinitelooping is specified.

Another behavior sequencer is an all-fork sequence. An all-fork sequenceis completed when all of its child nodes have finished executing. Anany-fork sequence is similar in that it is completed when any of itschild nodes has finished executing. The all-fork and any-fork sequencesemulate multi-threading for processing on resource-limited devices sothat the spawning of more threads is more easily controlled.

An if-else-fork sequence is a further behavior sequencer, whichconditionally executes different ones of its child nodes dependent uponthe state of a sensor. For example, an if-else-fork sequence having twochild nodes may execute one child node when a sensor is active, in thata condition monitored by a sensor is detected, whereas the other childnode may be executed when the condition is not detected. The sensorfunction is abstract and may represent such device-related conditions asa key depression or release, and receipt of a communication signal.

Each behavior sequencer may itself also be a parent or child node of anyother behavior sequencer. Using combinations of behavior sequencers andbehaviors, many different scene behaviors may be emulated byconstructing a sequence graph based on original rich content.

The present invention is in no way limited to the above examplebehaviors and behavior sequencers. Content converters and contentproviders may be configured to handle new behaviors and behaviorsequencers developed to support additional rich content functionality ondevices.

Time-based behaviors have a beginning and an end. A sequence graph isscheduled from an outermost behavior to one or more innermost behaviorsand is run until the outermost behavior is finished.

The sequence graph 900 is representative of the timed operation oftime-based behaviors, with the outermost timed loop indicated by the topmember of the graph. In FIG. 11, an any-fork behavior sequencer 905 isthe outermost behavior that controls the operation of this scene. Belowthe any-fork node 905 is a loop represented by linear sequence 910 withthe argument “loop=true”, indicating that looping is enabled. This loopincludes a hotspot 915 which specifies a target node which is the image820 in visual graph 800, and a play audio clip behavior 920. In thisloop, the activation of the hotspot 915 by navigating a cursor orpointer over the hotspot 915 causes an audio clip, designated “myclip”in FIG. 11, to be played by the play audio clip behavior 920. The clipplays until it is completed, at which time the hotspot 915 may beactivated to play the clip again.

The interpolate behaviors 935, 940, 945 translate their respectivetarget objects by interpolating new object positions based on aninterpolation curve and an elapsed time since the behavior was lastexecuted. The interpolate behaviors 935, 940, 945 respectively move the“Hello, World” text 825, the rectangle 815, and group B 810, whichcomprises the “face.gif” image 820 and the “Hello, World” text 825.

The visual graph 800 and the sequence graph 900 are processed by themedia engine 530 in a series of passes. In each pass, elements in thegraphs are processed. Processor time allotments are provided to each ofthe elements as needed by the elements.

This time allotment may be managed in a variety of ways, including, forexample, sharing a predetermined single pass time between all behaviorsin a sequence graph or allowing each behavior to complete a particularportion of its associated operations in each pass.

Alternately, a processor may also track execution times of each pass andpossibly each behavior, such that time-dependent behaviors may determinean elapsed time since its preceding pass, cumulative execution time(i.e. total elapsed time since the beginning of the first pass), andpossibly other times associated with sequence graph processing, asrequired.

A first pass through the sequence graph 900, for example, proceeds asfollows. The outermost behavior sequencer, the any-fork sequence 905,controls the completion of the sequence graph operations. As describedabove, an any-fork sequence is completed when any one of its childrenhas finished executing. In the sequence graph 900, the linear sequence910 is processed first. The first behavior, the hotspot 915, is allowedto execute to perform one or more particular functions.

Interpolate behaviors preferably have a specified total duration, suchthat associated translation operations are executed for a certain periodof time before ending. The total duration typically is specified as ameasure of time, but may instead be specified as a particular lengthalong an interpolation curve, a number of cycles around a closedinterpolation curve or some other type of limit controlling theexecution of the behavior.

An interpolate behavior effectively calculates a new position for atarget object based on an interpolation curve, an amount of time elapsedsince a preceding pass through the behavior, and possibly a preferredanimation “speed”. For example, in the first pass through the sequencegraph 900, the interpolate behavior 935 calculates a new position forthe “Hello, World” text 825 by interpolating a new position on aninterpolation curve using an elapsed time since the beginning of thefirst pass through the sequence graph. An interpolate behavioreffectively calculates a distance along the interpolation curve that thetarget object should have moved in the elapsed time and therebydetermines new coordinates for the target object. In each pass through asequence graph, the interpolate behavior 935 executes one interpolationcalculation.

An interpolation curve may be of virtually any shape and size, dependingupon the desired movements to be applied to a visual object. It shouldbe appreciated that interpolation curves are used by interpolatebehaviors but are not necessarily visual objects in a visual graph.Where one visual element is intended to move along a path that tracesanother visual element however, an interpolation curve may beestablished based on an element in a visual graph. In this case, aninterpolate behavior may reference a non-target object in the visualgraph to determine an interpolation curve to be used to control thebehavior of another object, the target object, in the visual graph.

Each of the interpolate behaviors 935, 940, 945 may, for example, use adifferent type of interpolation curve for its respective target object.For example, behavior 935 may use a circular interpolation curve to movethe text in a circular pattern, such as around the image “face.gif”,whereas behavior 940 may animate the rectangle back and forth along astraight-line interpolation curve. The behavior 945 may then move boththe text, which is moving around the image, and the image, in arectangular pattern around the edges of a display screen.

Thus, in a first pass through the sequence graph 900, the hotspotbehavior 915 establishes its target, the image 820, as a hotspot, andinterpolate behaviors 935, 940, 945 all interpolate new positions fortheir respective targets and reference their targets in the visual graph800 to move the visual elements 710 to their new positions on thedisplay 540 accordingly.

A second pass through the sequence graph 900 then begins. For thepurposes of this example, it is assumed that none of the behaviors havefinished executing in the first pass through the sequence graph 900. Theany-fork sequence 905 determines the status of its children by checking“finished” or similar flags or indicators, which are associated with andmay preferably be set by each behavior. When a behavior finishesexecuting, it may set a finished flag to true, for example. In thesequence graph 900, the any-fork sequence 905 ends processing of thesequence graph when any one of its children has set its completed flag.

In the second and subsequent passes through the sequence graph 900, eachbehavior resumes at whatever point it reached in the preceding pass. Thelinear sequence 910 is not yet complete, and resumes with the hotspotbehavior 915 to determine if the user has navigated to or over thehotspot image. To this end, user inputs may be queued or cached in amemory on a device and processed during sequence graph operations.

The hotspot behavior 915 checks the input queue to determine if a userhas navigated a cursor or other screen pointer over the hotspot. If so,the behavior 915 is finished and a finished flag is set to true toindicate to the linear sequencer 910 that it has completed. The playaudio clip behavior 920 is then started and a part of the audio clip“myclip” is played. Control then passes to the interpolate behaviors935, 940, 945, which in turn determine new positions for theirrespective target objects for rendering.

In the next pass, the any-fork sequence 905 again checks to see if anyof its behaviors have finished and if so, the sequence is completed.Otherwise, another pass through the sequence graph 900 is performed. Inthis pass, the hotspot behavior 915 has finished, so the linear sequence910 proceeds with the play audio clip behavior 920 to play another partof “myclip”. New positions of targets 825, 815, 810 are determined, andthe visual elements 710 are modified and rendered again.

Since looping is enabled in the linear sequence 910, the sequencerepeats once all of its child behaviors have completed. Therefore, theany-fork sequence 905 completes when one of the interpolate behaviors935, 940, 945 finishes. In a subsequent pass, the any-fork sequence 905detects the finished flag, or possibly otherwise determines that one ofits children has finished executing, and the sequence graph processingends.

The visual graph 800 and the sequence graph 900 are shown in FIGS. 10and 11 for illustrative purposes only. An animation may include fewer,more and different visual elements in a visual graph and behaviors andsequencers in a sequence graph. This provides for flexibility indefining many different animations or scenes, which may include amultitude of effects and animations. The interpolate sequences representonly one example of effects that may be applied to visual elements in avisual graph. Any attributes of visual elements in a visual graph,including position, size and color for example, may be modified. Visualelements and groups in a visual graph may also preferably be moved inother ways than being translated along an interpolation curve. Forexample, target objects in a visual graph may also or instead berotated. Many other effects could also be defined to emulate effects inoriginal rich content, and are within the scope of the presentinvention.

FIG. 12 is a flowchart of a method of converting rich content into abinary format. The rich content is a frame-based animation 1000, asdescribed above. The frame-based animation 1000 is first converted (byanimation converter 104) into SVG format at step 1002. The animation ofthe animation objects in the frame-based animation 1000 is convertedinto SVG animate tags, as described above. The SVG content created atstep 1002 is then converted (by converter 510) into a binary format (BF)at step 1004. The BF content comprises a visual graph and a sequencegraph, as described above.

The frame-based animation 1000 may also contain script, includingget-URL, tell-target, play and stop commands, as described above.Get-Url commands are converted into SVG anchor tags, which are denotedwith “a” tags in the SVG content created at step 1002, and which specifyan attribute value containing the URL of the content to be loaded.Alternatively, get-Url commands may be converted into “loadScene” tags,which specify the URL of the content to be loaded and a triggercondition which specifies when the content is to be loaded. The tags arethen converted into hyperlink nodes in the binary format created at1004. Tell-target, play and stop commands specify a sprite animation andwhen it should be played. This information is specified by SVG animatetags at step 1002, which are converted into interpolate behaviors in thesequence graph at step 1004.

Script is executed in response to button actions and frame actions inthe frame-based animation 1000. A frame action can be expressed as atime-offset from the beginning of the animation at which the script isexecuted. The time-offset is represented by a begin-attribute in theanimate tag in the SVG content created at step 1002. The begin-attributespecifies the amount of time which passes after the beginning of theanimation before the script is executed. The offset is represented inthe sequence graph created at step 1004 by an interpolate behavior whichhas no target animation object. The interpolate behavior thus takes timeto execute and has no effect on the display of the rich content. Whenthe interpolate behavior is completed, processing of the sequence graphcontinues with nodes in the sequence graph which correspond to script inthe frame-based animation 1000.

Button actions are represented in the SVG created at step 1002 by anchortags, or by “begin” attributes of animate or “loadScene” tags, which areused to specify the trigger condition of a corresponding button action.Button actions are represented in the sequence graph created at step1004 by hotspot behaviors. Nodes corresponding to the script in theframe-based animation are descendents of the hotspot behavior in thesequence graph, so that when the target animation object specified bythe hotspot behavior is activated, the part of the sequence graph thatcorresponds to the script in the frame-based animation 1000 is executed.

The sequence graph nodes representing the frame-based animation 1000 aredescendent nodes of a linear sequence behavior sequencer. If theframe-based animation 1000 loops, then the linear sequence specifiesthat looping is enabled. Any-fork and all-fork behavior sequencers areused to control the execution of the sequence graph, as described above,so that the BF content created at step 1004 is equivalent to theframe-based animation 1000, in that they appear the same when they aredisplayed.

The BF content that is created at step 1004 is a binary representationof the frame-based animation 1000. The BF representation minimizes theamount of data required to represent the rich content, thus minimizingthe time required to transmit the data across a network and the amountof storage space required to store the content on a device such as amobile communication device or a personal computer. In addition, wherethe frame-based animation 1000 comprises frames and animation objectsand further comprises script, the BF content created at step 1004represents the same content with only a visual graph and a sequencegraph. Therefore, no scripting support is required for software whichrenders rich content in BF format.

FIG. 13 is a block diagram of an example animation. The visualrepresentation 1100 of the animation illustrates a triangle which ismoving downward and to the right. The animation is represented byframe-based content 1102 which includes script. The script includestell-target and play script commands which are to be executed inresponse to frame actions. When converted into SVG as described above,the animation is represented by XML code 1104. The XML code 1104includes an interpolator 120 in the form of an “animateTransform” tag,which is an example of an animate tag which displays the spritespecified by the script commands in the frame-based content 1102. TheXML code also includes an animation object 116 as defined by a pathelement. As seen in XML code 1104, the “animate Transform” tag specifieda target display property “transform”, a duration “dur”, and a pluralityof key times, with values for the target display properties at each ofthe key times.

When the XML code 1104 is converted into BF content as described above,the animation is represented by a visual graph 1106 and a sequence graph1108. The animation objects included in the animation are represented bythe rectangle node 1112, polygon nodes 1116, 1118, and group nodes 1110,1114 in the visual graph 1106. The linear sequence node 1120 is theoutermost node of the sequence graph 1108, which controls the display ofthe animation. The interpolate node 1122 which does not specify a targetis executed first, creating a time offset which corresponds to the frameaction in response to which the script in the frame-based content 1102is to be executed. Once the interpolate node 1122 has finishedexecuting, the all-fork node 1126 executes the any-fork nodes 1124,1128, which in turn execute the interpolate nodes 1130, 1132, 1134, 1136which specify target nodes in the display graph 1106, thus displayingthe sprite specified by the script commands in the framed-based content1102. The times listed in the interpolate nodes are represented inmilliseconds.

FIG. 14 is a block diagram of a dual-mode mobile communication device.The media devices 405, for example, include the dual-mode mobilecommunication device 1210.

The dual-mode device 1210 includes a transceiver 1211, a microprocessor1238, a display 1222, Flash memory 1224, RAM memory 1226, auxiliaryinput/output (I/O) devices 1228, a serial port 1230, a keyboard 1232, aspeaker 1234, a microphone 1236, a short-range wireless communicationssub-system 1240, and may also include other device sub-systems 1242. Thetransceiver 1211 preferably includes transmit and receive antennas 1216,1218, a receiver 1212, a transmitter 1214, one or more local oscillators1213, and a digital signal processor 1220. Within the Flash memory 1224,the device 1210 preferably includes a plurality of software modules1224A–1224N that can be executed by the microprocessor 1238 (and/or theDSP 1220), including a voice communication module 1224A, a datacommunication module 1224B, and a plurality of other operational modules1224N for carrying out a plurality of other functions.

The mobile communication device 1210 is preferably a two-waycommunication device having voice and data communication capabilities.Thus, for example, the device may communicate over a voice network, suchas any of the analog or digital cellular networks, and may alsocommunicate over a data network. The voice and data networks aredepicted in FIG. 14 by the communication tower 1219. These voice anddata networks may be separate communication networks using separateinfrastructure, such as base stations, network controllers, etc., orthey may be integrated into a single wireless network.

The communication subsystem 1211 is used to communicate with the voiceand data network 1219, and includes the receiver 1212, the transmitter1214, the one or more local oscillators 1213 and may also include theDSP 1220. The DSP 1220 is used to send and receive signals to and fromthe transmitter 1214 and receiver 1212, and is also utilized to receivecontrol information from the transmitter 1214 and to provide controlinformation to the receiver 1212. If the voice and data communicationsoccur at a single frequency, or closely-spaced set of frequencies, thena single local oscillator 1213 may be used in conjunction with thetransmitter 1214 and receiver 1212. Alternatively, if differentfrequencies are utilized for voice communications versus datacommunications, then a plurality of local oscillators 1213 can be usedto generate a plurality of frequencies corresponding to the voice anddata networks 1219. Although two antennas 1216, 1218 are depicted inFIG. 14, the mobile device 1210 could be used with a single antennastructure. Information, which includes both voice and data information,is communicated to and from the communication module 1211 via a linkbetween the DSP 1220 and the microprocessor 1238. The detailed design ofthe communication subsystem 1211, such as frequency band, componentselection, power level, etc., will be dependent upon the communicationnetwork 1219 in which the device is intended to operate. For example, adevice 1210 intended to operate in a North American market may include acommunication subsystem 1211 designed to operate with the Mobitex™ orDataTAC™ mobile data communication networks and also designed tooperated with any of a variety of voice communication networks, such asAMPS, TDMA, CDMA, PCS, etc., whereas a device 1210 intended for use inEurope may be configured to operate with the General Packet RadioService (GPRS) data communication network and the GSM voicecommunication network. Other types of data and voice networks, bothseparate and integrated, may also be utilized with the mobile device1210.

Depending upon the type of network 1219 (or networks), the accessrequirements for the dual-mode mobile device 1210 may also vary. Forexample, in the Mobitex™ and DataTAC™ data networks, mobile devices areregistered on the network using a unique identification numberassociated with each device. In GPRS data networks, however, networkaccess is associated with a subscriber or user of a device 1210. A GPRSdevice typically requires a subscriber identity module (“SIM”), which isrequired in order to operate the device 1210 on a GPRS network. Local ornon-network communication functions (if any) may be operable, withoutthe SIM device, but the device 1210 will be unable to carry out anyfunctions involving communications over the data network 1219, otherthan any legally required operations, such as 911 emergency calling.

After any required network registration or activation procedures havebeen completed, the dual-mode device 1210 may the send and receivecommunication signals, including both voice and data signals, over thenetwork 1219 (or networks). Signals received by the antenna 1216 fromthe communication network 1219 are routed to the receiver 1212, whichprovides for signal amplification, frequency down conversion, filtering,channel selection, etc., and may also provide analog to digitalconversion. Analog to digital conversion of the received signal allowsmore complex communication functions, such as digital demodulation anddecoding to be performed using the DSP 1220. In a similar manner,signals to be transmitted to the network 1219 are processed, includingmodulation and encoding, for example, by the DSP 1220 and are thenprovided to the transmitter 1214 for digital to analog conversion,frequency up conversion, filtering, amplification and transmission tothe communication network 1219 (or networks) via the antenna 1218.Although a single transceiver 1211 is shown in FIG. 14 for both voiceand data communications, it is possible that the device 1210 may includetwo distinct transceivers, a first transceiver for transmitting andreceiving voice signals, and a second transceiver for transmitting andreceiving data signals.

In addition to processing the communication signals, the DSP 1220 alsoprovides for receiver and transmitter control. For example, the gainlevels applied to communication signals in the receiver 1212 andtransmitter 1214 may be adaptively controlled through automatic gaincontrol algorithms implemented in the DSP 1220. Other transceivercontrol algorithms could also be implemented in the DSP 1220 in order toprovide more sophisticated control of the transceiver 1211.

The microprocessor 1238 preferably manages and controls the overalloperation of the dual-mode mobile device 1210. Many types ofmicroprocessors or microcontrollers could be used here, or,alternatively, a single DSP 1220 could be used to carry out thefunctions of the microprocessor 1238. Low-level communication functions,including at least data and voice communications, are performed throughthe DSP 1220 in the transceiver 1211. Other, high-level communicationapplications, such as a voice communication application 1224A, and adata communication application 1224B may be stored in the Flash memory1224 for execution by the microprocessor 1238. For example, the voicecommunication module 1224A may provide a high-level user interfaceoperable to transmit and receive voice calls between the dual-modemobile device 1210 and a plurality of other voice devices via thenetwork 1219. Similarly, the data communication module 1224B may providea high-level user interface operable for sending and receiving data,such as e-mail messages, files, organizer information, short textmessages, etc., between the dual-mode mobile device 1210 and a pluralityof other data devices via the network 1219. The microprocessor 1238 alsointeracts with other device subsystems, such as the display 1222, Flashmemory 1224, random access memory (RAM) 1226, auxiliary input/output(I/O) subsystems 1228, serial port 1230, keyboard 1232, speaker 1234,microphone 1236, a short-range communications subsystem 1240 and anyother device subsystems generally designated as 1242.

Some of the subsystems shown in FIG. 14 perform communication-relatedfunctions, whereas other subsystems may provide resident or on-devicefunctions. Notably, some subsystems, such as keyboard 1232 and display1222 may be used for both communication-related functions, such asentering a text message for transmission over a data communicationnetwork, and device-resident functions such as a calculator or task listor other PDA type functions.

Operating system software used by the microprocessor 1238 is preferablystored in a persistent store such as Flash memory 1224. In addition tothe operating system, which controls all of the low-level functions ofthe device 1210, the Flash memory 1224 may include a plurality ofhigh-level software application programs, or modules, such as a voicecommunication module 1224A, a data communication module 1224B, anorganizer module (not shown), or any other type of software module1224N. Where of the media devices 105 includes the dual-mode mobilecommunication device 1210, another software module 1224N implements themedia engine 530, as described above. The Flash memory 1224 also mayinclude a file system for storing data. These modules are executed bythe microprocessor 1238 and provide a high-level interface between auser of the device and the device. This interface typically includes agraphical component provided through the display 1222, and aninput/output component provided through the auxiliary I/O 1228, keyboard1232, speaker 1234, and microphone 1236. The operating system, specificdevice applications or modules, or parts thereof, may be temporarilyloaded into a volatile store, such as RAM 1226 for faster operation.Moreover, received communication signals may also be temporarily storedto RAM 1226, before permanently writing them to a file system located inthe flash memory 1224.

An exemplary application module 1224N that may be loaded onto thedual-mode device 1210 is a personal information manager (PIM)application providing PDA functionality, such as calendar events,appointments, and task items. This module 1224N may also interact withthe voice communication module 1224A for managing phone calls, voicemails, etc., and may also interact with the data communication modulefor managing e-mail communications and other data transmissions.Alternatively, all of the functionality of the voice communicationmodule 1224A and the data communication module 1224B may be integratedinto the PIM module.

The Flash memory 1224 preferably provides a file system to facilitatestorage of PIM data items on the device. The PIM application preferablyincludes the ability to send and receive data items, either by itself,or in conjunction with the voice and data communication modules 1224A,1224B, via the wireless network 1219. The PIM data items are preferablyseamlessly integrated, synchronized and updated, via the wirelessnetwork 1219, with a corresponding set of data items stored orassociated with a host computer system, thereby creating a mirroredsystem for data items associated with a particular user.

The mobile device 1210 may also be manually synchronized with a hostsystem by placing the device 1210 in an interface cradle, which couplesthe serial port 1230 of the mobile device 1210 to the serial port of thehost system. The serial port 1230 may also be used to enable a user toset preferences through an external device or software application, orto download other application modules 1224N for installation. This wireddownload path may be used to load an encryption key onto the device,which is a more secure method than exchanging encryption information viathe wireless network 1219.

Additional application modules 1224N may be loaded onto the dual-modedevice 1210 through the network 1219, through an auxiliary I/O subsystem1228, through the serial port 1230, through the short-rangecommunications subsystem 1240, or through any other suitable subsystem1242, and installed by a user in the Flash memory 1224 or RAM 1226. Suchflexibility in application installation increases the functionality ofthe device 1210 and may provide enhanced on-device functions,communication-related functions, or both. For example, securecommunication applications may enable electronic commerce functions andother such financial transactions to be performed using the device 1210.

When the dual-mode device 1210 is operating in a data communicationmode, a received signal, such as a text message or a web page download,will be processed by the transceiver 1211 and provided to themicroprocessor 1238, which will preferably further process the receivedsignal for output to the display 1222, or, alternatively, to anauxiliary I/O device 1228. A user of dual-mode device 1210 may alsocompose data items, such as email messages, using the keyboard 1232,which is preferably a complete alphanumeric keyboard laid out in theQWERTY style, although other styles of complete alphanumeric keyboardssuch as the known DVORAK style may also be used. User input to thedevice 1210 is further enhanced with a plurality of auxiliary I/Odevices 1228, which may include a thumbwheel input device, a touchpad, avariety of switches, a rocker input switch, etc. The composed data itemsinput by the user may then be transmitted over the communication network1219 via the transceiver 1211.

When the dual-mode device 1210 is operating in a voice communicationmode, the overall operation of the device 1210 is substantially similarto the data mode, except that received signals are preferably be outputto the speaker 1234 and voice signals for transmission are generated bya microphone 1236. Alternative voice or audio I/O subsystems, such as avoice message recording subsystem, may also be implemented on the device1210. Although voice or audio signal output is preferably accomplishedprimarily through the speaker 1234, the display 1222 may also be used toprovide an indication of the identity of a calling party, the durationof a voice call, or other voice call related information. For example,the microprocessor 1238, in conjunction with the voice communicationmodule and the operating system software, may detect the calleridentification information of an incoming voice call and display it onthe display 1222.

A short-range communications subsystem 1240 may also be included in thedual-mode device 1210. For example, the subsystem 1240 may include aninfrared device and associated circuits and components, or a Bluetooth™short-range wireless communication module to provide for communicationwith similarly-enabled systems and devices.

It will be appreciated that the above description relates to embodimentsby way of example only. Many variations on the invention will be obviousto those knowledgeable in the field, and such obvious variations arewithin the scope of the invention as described, whether or not expresslydescribed.

For example, although the systems and methods according to aspects ofthe invention as described herein are particularly suited to mediadevices, the content size and processing requirement reductions may alsobe advantageous in other systems such as desktop computer systems andthe like in which memory and processing resources are not as limited asin media devices. Smaller file sizes and less intensive processingresults in faster content transfer and display.

It should also be appreciated that content converters and processors arenot dependent upon any particular communication networks, systems orprotocols. As such, content converters and processors in accordance withthe present invention may be implemented in virtually any one-way ortwo-way communication device. Communication-related dependencies areaddressed in the communication subsystems in content provider systemsand devices.

Although only two media devices and one wireless network, gateway, WANand content provider system have been shown in the drawings, it will beobvious that a communication system will normally include many suchcomponents. A content provider system may be configured to communicatewith multiple gateways and different wireless networks, possibly throughdifferent types of connections to different gateways. Each wirelessnetwork normally includes multiple gateways and provides communicationservices to thousands or even millions of devices, any or all of whichmay be enabled for communications with one or more content providersystems.

Furthermore, while the external converter and the converter aredescribed in the context of the content provider system described above,the external converter and the converter may be used in any system whichrequires conversion of rich content. In addition, while the externalconverter and the converter are described as distinct entities, theexternal converter and converter may be combined into one entity whichhas the functionality of both. Additionally, while the animations aredescribed as being contained in computer-readable files, they may alsobe contained in other computer-readable memory and data structures.Also, the system and method described can convert frame-based animationswhich are formatted differently from the example provided, and canconvert to interpolator-based animations which are formatted differentlyfrom the example provided. For example, the normalization of key-times,and the manner in which depths are specified may differ.

1. A method for converting a frame-based animation into aninterpolator-based animation, the frame based animation including aplurality of animation objects and a plurality of successive framesrepresented by frame instructions, the frames including a displayedgroup of the animation objects, the animation objects in the displayedgroup having associated display properties that change throughout thesuccessive frames, the animation objects in the displayed group eachappearing at a unique associated depth in the frames, the frameinstructions identifying for each frame the animation objects from thedisplayed group appearing therein and the display properties and depthassociated with each of the animation objects appearing therein, themethod including steps of: a) identifying each unique combination ofanimation object and associated depth identified in the frameinstructions for the plurality of frames; b) for each identified uniquecombination, identifying the display properties associated with theanimation object of the combination through the successive frames; andc) for each identified display property for each identified uniquecombination, creating an interpolator associated with the animationobject of the combination which specifies any changes that occur in thedisplay property for the specified animation object throughout theplurality of frames.
 2. The method of claim 1 wherein each uniquecombination of animation object and associated depth is identified by aunique key based on an identifier for the animation object and a valueassigned to the associated depth.
 3. The method of claim 1 wherein eachanimation object in the plurality of animation objects has a unique typeidentifier associated therewith, each of the depths having a uniquedepth value, wherein each unique combination of animation object andassociated depth is identified by a unique key based on the depth valueassociated with the depth of the unique combination and on the typeidentifier associated with the animation object of the combination. 4.The method of claim 3 wherein the key is a numerical value having firstand second parts wherein a value for the first part is set based on thedepth value associated with the depth of the unique combination and avalue for the second part is set based on the type identifier associatedwith the animation object of the combination, the first part being amore significant part of the numerical value than the second part. 5.The method of claim 1 wherein the frames of the animation object have anassociated frame rate, wherein step (b) includes determining a relativetime identifier for each change in each identified display propertybased on the frame rate and the number of frames, and step (c) includesspecifying in each interpolator the relative time identifiers for eachof the changes in the display property specified therein.
 6. The methodof claim 1 wherein the frames have an associated frame rate specified inthe frame instructions and steps (a), (b) and (c) collectively includesteps of: (1) creating a key list, and for each animation objectappearing in each frame identified in the frame instructions performingsteps of: (i) generating a key that specifies an identifier associatedwith the animation object and a depth value associated with the depth atwhich the animation object appears; (ii) determining if the key ispresent in the key list and (A) if the key is not present in the keylist, adding the key to the key list, creating a table that isassociated with the key, and recording in the associated table thedisplay properties associated with the animation object for the frame;and (B) if the key is present in the key list, determining if any of thedisplay properties associated with the animation object have changedsince being last recorded in the associated table, and if so, recordinga key-time based on a relative location of the frame in the plurality offrames and the frame rate and updating the associated table to record,in association with the key-time, any changes in the respective displayproperties associated with the animation object that have changed sincethe respective display properties associated with the animation objectwere last recorded; (2) processing each table, including for each tablecreating an interpolator for each display property for which a changetherein has been recorded in the table, the interpolator specifying (i)an identifier identifying the animation object associated with the keyassociated with the table; (ii) any changes in the display propertyoccurring throughout the plurality of frames; and (iii) for each of thespecified changes, a key-time assigning a relative time value to thechange; and (3) outputting as an interpolator based animation theplurality of animation objects and the interpolators.
 7. The method ofclaim 6 wherein prior to step (2), the key list is sorted into adescending order based on the depth values; in step (2) the tables areprocessed in an order based on of the keys in the key list; and in step(3) the interpolators are output in an order corresponding to an orderin which the interpolators were created in step (2).
 8. The method ofclaim 1 wherein the plurality of animation objects includes shapes,images, buttons and text.
 9. The method of claim 1 wherein the displayproperties associated with the animation objects in the displayed groupinclude position, visibility, color, scale, rotation and skew.
 10. Themethod of claim 1 wherein at least some of the frames include sprites,each sprite including a plurality of successive sub-frames, thesub-frames including a sprite displayed group of the animation objects,the animation objects in the sprite displayed group having associateddisplay properties that change throughout the successive sub-frames, theanimation objects in the sprite displayed group each appearing at aunique associated depth in the sub-frames, the frame instructionsidentifying for each frame any sprites appearing therein, and for eachsprite the animation objects from the sprite displayed group appearingtherein and the display properties and depth associated with each of theanimation objects appearing in the sprite, the method including stepsof: a) for each sprite, identifying each unique sprite combination ofanimation object and associated depth identified in the frameinstructions for the plurality of sub-frames of the sprite; b) for eachidentified unique sprite combination, identifying the display propertiesassociated with the animation object of the combination through thesuccessive sub-frames; and c) for each identified display property foreach identified unique sprite combination, creating an interpolator thatspecifies the animation object of the combination and any changes thatoccur in the display property for the specified animation objectthroughout the plurality of sub-frames.
 11. A converter for converting aframe-based animation into an interpolator based animation, theframe-based animation including a plurality of animation objects eachhaving an associated type identifier and a plurality of successiveframes represented by frame instructions, the frames including adisplayed group of the animation objects, the animation objects in thedisplayed group having associated display properties that changethroughout the successive frames, the animation objects in the displayedgroup each appearing at a unique associated depth in the frames, theframe instructions specifying for each frame the animation objectsappearing therein, and display properties and associated depth of theanimation objects appearing therein, the interpolator based animationincluding the plurality of animation objects and a plurality ofinterpolators, each interpolator being associated with a target displayproperty of a target animation object type selected from the pluralityof animation objects and specifying changes that occur in the targetdisplay property during a display duration, the converter including: aninput module for receiving a frame based animation and extracting theframe instructions therefrom; a converter module for (a) receiving theextracted frame instructions from the input module and based thereonidentifying each unique combination of animation object and associateddepth appearing in the plurality of frames, and (b) for each identifiedunique combination, identifying the display properties associated withthe animation object of the combination through the plurality of frames;and an output module responsive to the converter module for creating foreach identified display property for each identified unique combinationan interpolator specifying (i) the identified display property as atarget display property, (ii) the animation object of the combination asa target animation object, and (iii) any changes that occur in thedisplay property for the specified animation object throughout theplurality of frames.
 12. The converter of claim 11 wherein the convertermodule includes means for generating, for each identified uniquecombination, a unique identifying key based on a depth value associatedwith the depth of the unique combination and on the type identifierassociated with the animation object of the combination.
 13. Theconverter of claim 12 wherein the key is a numerical value having firstand second parts wherein a value for the first part is set based on thedepth value associated with the depth of the unique combination and avalue for the second part is set based on the type identifier associatedwith the animation object of the combination, the first part being amore significant part of the numerical value than the second part. 14.The converter of claim 13 wherein one of the converter module and outputmodule is configured for sorting the identifying keys based on the firstpart, and the output module is configured for outputting theinterpolators in an order that corresponds to the sorted identifyingkeys of the unique combinations that the interpolators have been createdfor.
 15. The converter of claim 11 wherein the plurality of successiveframes have an associated frame rate, wherein the converter module isalso for determining a relative time identifier for each change in eachidentified display property based on the frame rate and the relativelocation of the frame in which the change occurs in the plurality offrames, and specifying in each interpolator the relative timeidentifiers for each of the changes in the display property specifiedtherein.
 16. The converter of claim 15 wherein the time identifiers arenormalized such that each of the time identifiers has a value betweenzero to one.
 17. The converter of claim 11 wherein the plurality ofanimation objects includes shapes, images, buttons and text.
 18. Theconverter of claim 11 wherein the display properties associated with theanimation objects in the displayed group include position, visibility,color, scale, rotation and skew.
 19. The converter of claim 11 whereinthe interpolator-based animation is outputted in an XML compliant formatwith the interpolators represented as animate tags.
 20. The converter ofclaim 19 wherein at least some of the animation objects in theinterpolator-based animation are represented as path elements in the XMLcompliant format.